The PLEXCenter has developed a number of group decision support tools to enhance the decision making process. This paper proposes a new application for the PLEXCenter tools in the Information Systems (IS) planning environment. Models for organizational Strategic, Theater, and Tactical IS planning are proposed, and frameworks for implementation of the planning models using the PLEXCenter tools are developed. The frameworks make use of the existing PLEXCenter tools and, when a new tool is required, design specifications are presented to meet that new requirement. Keywords: Theses, Scenarios, Systems engineering, Flow charting, Integrated information systems.